doc: fix verbatim sections for vmxnet3
doc: fix verbatim sections for vmxnet3

Fixed two verbatim text sections in vmxnet3 docs.

Signed-off-by: John McNamara <af31595c36a4239b9676e9b3a777d3e2f15a6c4d@intel.com>
Acked-by: Yong Wang <0cd1be787884a033c98e298059e386114d22793e@vmware.com>

tsphillips/dpdk-fork,mixja/dpdk,john-mcnamara-intel/dpdk,tsphillips/dpdk-fork,mixja/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,msune/dpdk,mixja/dpdk,john-mcnamara-intel/dpdk,msune/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,msune/dpdk,venkynv/dpdk-mirror,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,mixja/dpdk,msune/dpdk,venkynv/dpdk-mirror